This invention relates to electro-surgical devices, and more particularly to improved electro-surgical devices having selectively insulated portions for use in resection and cauterization procedures.
There are many medical procedures in which tissue is cut or carved away for diagnostic or therapeutic reasons. For example, a transurethral resectioning of the prostate (TURP) is performed to treat benign or cancerous prostatic hyperplasia. Transurethral resectioning may also be performed in the bladder (TURB). The obstructing tissue can be resected, ablated, or coagulated with any number of electro-cautery devices which are inserted into the urethra through a resectroscope. An electric current heats the tissue sufficiently to break inter-cellular bonds, cutting the tissue, or denaturing the tissue in order to remove or perform coagulation on tissue.
Extensive bleeding can occur as a result of electro-resectioning, which can obstruct the physician""s view and lead to dangerous blood loss levels. Additionally, during these procedures a pressure differential exists between the urinary tract and the circulatory system. This pressure differential may result in an uptake of ambient fluid during the procedure, possibly causing complications. The bleeding can be treated or avoided by coagulating the tissue in the treatment area with an electro-coagulator that applies a low level current to denature cells to a sufficient depth without breaking intercellular bonds.
Existing electro-cautery devices tend to be inefficient when used with an electrolytic fluid such as saline, because energy applied to a resecting electrode rapidly diffuses into the fluid and chips that have already been removed, due to the conductive nature of the fluid and tissue. As a result, resection is either inadequately carried out, or a greater amount of energy is applied to the electrode to perform resectioning, raising a concern that adjacent healthy tissues may be damaged during the resectionig procedure.
It is therefore an object of the invention to provide an electrosurgical probe that can adequately perform electro-cautery while focusing the energy on the desired location.
The present invention features an electrosurgical device that is made more efficient and safer than conventional electrosurgical probes by selectively coating portions of the electrode in the device with an insulative or dielectric coating. The present invention provides an appropriate insulative coating that is capable of remaining adhered to an electrode during a resectioning procedure, in which the electrode is subjected to extremely high temperatures and voltages. Various polymer materials including Teflon, and ceramic materials have been tried as insulative coatings, however, such materials have been known to crack under a high temperature environment and therefore are unsuitable as coating materials for resecting electrodes.
In one aspect, the invention features an electro-surgical device, having an elongated body, a pair of arms extending from a distal end of the elongated body, and a loop electrode connecting the pair of arms. The elongated body is adapted to be coupled to a source of energy at a proximal end. The loop electrode defines a pair of end sections and a base section, and is formed of a conductive material. Each end section is coupled to an aim and comprises the conductive material having an insulative coating disposed thereon. The base section disposed between the end sections comprises the conductive material free of the insulative coating, thereby focusing energy emission to the tissue undergoing resection and cauterization.
In one embodiment, the insulative coating on the end sections can be a diamond-like coating or other coating having sufficient properties permitting it to withstand high voltages and temperatures. In another embodiment, the diamond-like coating can be vapor deposited onto the end sections. The insulative coating can have a thickness up to about 10 microns.
In another embodiment, the electro-surgical device comprises an elongated body, a pair of arms extending from a distal end of the elongated body, and an electrode in communication with the pair of arms. The elongated body is adapted to be coupled to a source of energy at a proximal end. The electrode has a first region covered with an insulative coating and a second region covered with a sacrificial material. The sacrificial material covering the second region disintegrates during the application of normal energy levels, exposing a conductive region underneath.
In another embodiment, the insulative coating can be vapor deposited on the first region, and the sacrificial material can be deposited on the second region by dipping, spraying, or brushing. The insulative coating is capable of remaining adhered to the first region upon application of a voltage of up to from about 1000 volts to about 2000 volts (rms) at mains frequency. The insulative coating can be a diamond-like coating.
In still another embodiment, the electro-surgical device comprises an elongated body, a pair of arms extending from a distal end of the elongated body, and an electrode in communication with the pair of arms. The elongated body is adapted to be coupled to a source of energy at a proximal end. The electrode has a non-uniformly deposited insulative coating capable of remaining adhered to the electrode upon application of a voltage of up to about 200 volts (rms), wherein the areas where the coating is thinner can degrade exposing the portion of the electrode which comprises the second region, focusing energy emission.
In another embodiment, the insulative coating can have a hardness of greater than 1000 kg/mm2, a dielectric strength of greater than about 100 volts (rms) per xcexcm and an electrical resistivity in the range from 102 ohm-cm to 102 ohm-cm. In yet another embodiment, the electrode can be a cylindrical roller electrode, or a spherical roller electrode.
In another aspect, the invention features a resectoscope assembly. The assembly includes a resectoscope having a channel and an electro-surgical device insertable through the channel. The electro-surgical device includes an elongated body, a pair of arms in communication with the elongated body and a distal electrode in communication with the pair of arms. The electrode has a first region coated with an insulative coating and a second region for focusing energy emission. The insulative coating is capable of remaining adhered to the electrode upon application of a voltage of up to 500 volts (rms) at mains frequency.
In still another aspect, the invention features a method for performing selective cauterization. An electro-surgical device is positioned along a treatment path near tissue to be resected. The electro-surgical device includes an elongated body, a pair of arms in communication with the elongated body and a distal electrode in communication with the pair of arms. The electrode has a first region coated with an insulative coating and a second region for focusing energy emission. The insulative coating is capable of remaining adhered to the electrode upon application of a voltage of up to 500 volts (rms) at mains frequency. The tissue is flushed with a non-osmotic fluid. A plasma field is generated near the second region of the electrode and the tissue. The electro-surgical device is moved along the treatment path to resect and coagulate the tissue.
In each of the above embodiments, the electro-surgical device can be efficiently used with a non-osmotic fluid, such as, for example, saline, glycine or sorbitol. Moreover, the electro-surgical device of the present invention can be used in saline, an electrolytic, non-osmotic fluid without a considerable loss of energy to the tissue undergoing treatment or the fluid. Additionally, the present invention avoids the use of high currents to deliver energy to the treatment site, as energy is effectively focused in the conductive section or sections of the electrode. The result is higher current density, which promotes the generation of a plasma field.
The foregoing and other objects, features, and advantages of the invention will become apparent from the following, more particular description of the preferred embodiments of the invention.
This invention is described with particularity in the appended claims. The above and further advantages of this invention may be better understood by referring to the following description taken in conjunction with the accompanying drawings.
FIG. 1a is a perspective view of an electro-surgical device positioned within a resectoscope.
FIG. 1b is a perspective view of the electro-surgical device of FIG. 1a. 
FIG. 2 is an enlarged perspective view of a-distal portion of the electro-surgical device of FIG. 1a. 
FIG. 3 is an enlarged top view of the distal portion of the electro-surgical device of FIG. 1.
FIG. 4 is an enlarged cross-sectional side view of the distal portion of the electro-surgical device of FIG. 1a. 
FIGS. 5-9 are cross-sectional side views of the distal portion of the electro-surgical device of FIG. 1a in use within a urethra.
FIGS. 10 and 11 are cross-sectional side views illustrating structure and use of another embodiment of an electro-surgical device.
FIG. 12 is a side view of another embodiment of a resectoscope.
FIG. 13 is an exploded, side view of the resectoscope of FIG. 12.
FIG. 14 is an enlarged perspective view of a distal portion of an electro-surgical device used in conjunction with the resectoscope of FIG. 12.
FIG. 15 is an enlarged side view of a proximal portion of the electro-surgical device used lo in conjunction with the resectoscope of FIG. 12.
FIG. 16 is an enlarged partially cross-sectional view of a portion of the handle of the resectoscope of FIG. 12 and a bipolar power connector adaptor.
FIG. 17 is a perspective view of another bipolar power connector adaptor that can be used in conjunction with the resectoscope of FIG. 12.
FIG. 18 is an enlarged side view of a portion of the handle of the resectoscope of FIG. 12 in combination with the bipolar power connector adaptor of FIG. 17.
FIG. 19 is a perspective view of a power connector adaptor for use in conjunction with another type of resectoscope.
FIG. 20 is an enlarged side view, shown in partial cross-section, of the power connector adaptor of FIG. 18 and a portion of the handle of a resectoscope.
FIGS. 21a-21c are cross-sectional side views of the electro-surgical device of FIG. 12 in use within a urethra.
FIG. 22 is a side view of another electro-surgical device that can be used in conjunction with the resectoscope of FIG. 12.
FIG. 23 is a side view of another electro-surgical device in a retracted position within a distal portion of a resectoscope.
FIG. 24 is a side view of the electro-surgical device of FIG. 23 in an extended position within the distal portion of the resectoscope.
FIG. 25 is a cross-sectional view of the electro-surgical device of FIG. 23 within the distal portion of the resectoscope.
FIG. 26 is a side view of another electro-surgical device in an extended position within the distal end of a resectoscope.
FIG. 27a is a perspective view of an electro-surgical device having a loop electrode.
FIG. 27b is an enlarged perspective view of a distal portion of the electro-surgical device of FIG. 27a. 
FIG. 28 is a cross-sectional view of a dual ion beam deposition chamber for depositing an insulative coating on an electrode.
FIG. 29a is a perspective view of another electro-surgical device having a loop electrode.
FIG. 29b is an enlarged perspective view of a distal portion of the electro-surgical device of FIG. 29a. 
FIG. 30a is a perspective view of an electro-surgical device having a cylindrical roller electrode.
FIG. 30b is a perspective view of an electro-surgical device having a spherical roller electrode.
FIG. 31a is a perspective view of another electro-surgical device having a loop electrode.
FIG. 31b is an enlarged perspective view from a proximal side of a distal portion of the electro-surgical device of FIG. 31a. 
FIG. 32 is a side view illustrating selective resection and cauterization of prostate tissue using the electro-surgical device of the present invention.
FIG. 33a is a side view of a biopsy forcepxe2x80x94, and xe2x80x94FIG. 33b is an enlarged perspective view of a distal end of the biopsy forcep of FIG. 33a.